<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>
    
    console.log(typeof "hello");
    console.log(typeof "true");
    console.log(typeof "123123");
    console.log(typeof "{}");
    console.log(typeof "function(){}");
    console.log(typeof "undefined");

    console.log(typeof 123);
    console.log(typeof -123);
    console.log(typeof -123.345);
    console.log(typeof NaN);

    console.log(typeof true);
    console.log(typeof false);
    
    console.log(typeof undefined);
    
    console.log(typeof function(){});
    
    console.log(typeof {});
    console.log(typeof []);
    
    console.log(typeof null);


    // 注意点：（面试题）
    console.log(typeof typeof true);
    // typeof的检测结果以什么类型存在？字符
    // 多个typeof检测结果必然是string

</script>
</html>